Smartcard, chip card or integrated circuit card is typically any pocket-sized card with embedded integrated circuits. Contactless smartcards typically are RFID (Radio Frequency Identification) type cards which suffer from collision problems. Collisions can occur when more than one smartcard is in the vicinity of the reader device. To help address the collision problem, smartcards typically support card ID (Identification) codes.
Two types of ID codes are the fixed Unique ID (UID) and the Random ID. A fixed UID code typically serves two functions. The UID is used in the anti-collision process to distinguish between multiple cards presented in parallel in the vicinity of the reader device and address the cards individually. A UID is also used by the reader device to ascertain the identity of a hardcoded or virtual card device to determine which keys to use when addressing the device. The Random-ID code is typically newly generated at each Power-UP of the card and is stored in RAM. Hence, when a Random-ID code scheme is used by the card, the reader device typically receives a new Random-ID from the card each time the card is brought into the RF-field of the reader device.
Some applications that use fixed UIDs, typically in the customer card area, have been rejected by users or card issuers because a large number of users objected to the full trackability of the smartcards having UIDs from location to location. Particularly for smartcards with RFID or other contactless interfaces, protection against unwanted tracking of interactions with reader devices or tracking of location changes is typically desirable from a user point of view. The use of Random-IDs is recommended from both a security and privacy point of view for secure cards to prevent individual cards from being tracked from location to location where the Random-ID code is exposed during the anti-collision process.